/*
 * The maRla Project - Graphical problem solver for statistical calculations.
 * Copyright © 2011 Cedarville University
 * http://marla.googlecode.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/*
 * Copyright 2006-2008 Kees de Kooter
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package marla.opedit.gui.xmlpane;

import java.awt.Color;
import java.awt.Graphics;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.Element;
import javax.swing.text.PlainDocument;
import javax.swing.text.PlainView;
import javax.swing.text.Segment;
import javax.swing.text.Utilities;

/**
 * Thanks: http://groups.google.com/group/de.comp.lang.java/msg/2bbeb016abad270
 *
 * IMPORTANT NOTE: regex should contain 1 group.
 *
 * Using PlainView here because we don't want line wrapping to occur.
 *
 * @author kees
 * @date 13-jan-2006
 *
 */
public class XmlView extends PlainView
{
	private static final HashMap<Pattern, Color> patternColors;
	private static final String GENERIC_XML_NAME = "[A-Za-z]+[A-Za-z0-9\\-_]*(:[A-Za-z]+[A-Za-z0-9\\-_]+)?";
	private static final String TAG_PATTERN = "(</?" + GENERIC_XML_NAME + ")";
	private static final String TAG_END_PATTERN = "(>|/>)";
	private static final String TAG_ATTRIBUTE_PATTERN = "(" + GENERIC_XML_NAME + ")\\w*\\=";
	private static final String TAG_ATTRIBUTE_VALUE = "\\w*\\=\\w*(\"[^\"]*\")";
	private static final String TAG_COMMENT = "(<\\!--[\\w ]*-->)";
	private static final String TAG_CDATA = "(<\\!\\[CDATA\\[.*\\]\\]>)";

	static
	{
		// NOTE: the order is important!
		patternColors = new LinkedHashMap<Pattern, Color>();
		patternColors.put(Pattern.compile(TAG_PATTERN), new Color(63, 127, 127));
		patternColors.put(Pattern.compile(TAG_CDATA), Color.GRAY);
		patternColors.put(Pattern.compile(TAG_ATTRIBUTE_PATTERN), new Color(
				127, 0, 127));
		patternColors.put(Pattern.compile(TAG_END_PATTERN), new Color(63, 127,
																	  127));
		patternColors.put(Pattern.compile(TAG_ATTRIBUTE_VALUE), new Color(42,
																		  0, 255));
		patternColors.put(Pattern.compile(TAG_COMMENT), Color.BLUE);
	}

	public XmlView(Element element)
	{

		super(element);

		// Set tabsize to 4 (instead of the default 8)
		getDocument().putProperty(PlainDocument.tabSizeAttribute, 4);
	}

	@Override
	protected int drawUnselectedText(Graphics graphics, int x, int y, int p0,
									 int p1) throws BadLocationException
	{

		Document doc = getDocument();
		String text = doc.getText(p0, p1 - p0);

		Segment segment = getLineBuffer();

		SortedMap<Integer, Integer> startMap = new TreeMap<Integer, Integer>();
		SortedMap<Integer, Color> colorMap = new TreeMap<Integer, Color>();

		// Match all regexes on this snippet, store positions
		for(Map.Entry<Pattern, Color> entry : patternColors.entrySet())
		{

			Matcher matcher = entry.getKey().matcher(text);

			while(matcher.find())
			{
				startMap.put(matcher.start(1), matcher.end());
				colorMap.put(matcher.start(1), entry.getValue());
			}
		}

		// TODO: check the map for overlapping parts

		int i = 0;

		// Colour the parts
		for(Map.Entry<Integer, Integer> entry : startMap.entrySet())
		{
			int start = entry.getKey();
			int end = entry.getValue();

			if(i < start)
			{
				graphics.setColor(Color.black);
				doc.getText(p0 + i, start - i, segment);
				x = Utilities.drawTabbedText(segment, x, y, graphics, this, i);
			}

			graphics.setColor(colorMap.get(start));
			i = end;
			doc.getText(p0 + start, i - start, segment);
			x = Utilities.drawTabbedText(segment, x, y, graphics, this, start);
		}

		// Paint possible remaining text black
		if(i < text.length())
		{
			graphics.setColor(Color.black);
			doc.getText(p0 + i, text.length() - i, segment);
			x = Utilities.drawTabbedText(segment, x, y, graphics, this, i);
		}

		return x;
	}
}
